Evett & Shaw Elan loudspeaker Measurements

Sidebar 3: Measurements

As expected from its diminutive dimensions, the Elan is not very sensitive: my B-weighted estimate came in at just 82dB(B)/2.83V/1m. Compounding the low sensitivity is a very demanding impedance (fig.1) that dips well below 2 ohms between 300Hz and 700Hz, coupled with a generally demanding electrical phase angle. While this did not prove much of a liability in the desktop situation—the volume was annoying my neighbors before the Yamaha receiver's protection cut in—it's something to be aware of when using the Elans in larger rooms or more private offices. And forget tube amplifiers unless they have a beefy 2 ohm output transformer tap.

Fig.1 Evett & Shaw Elan, electrical impedance (solid) and phase (dashed). (2 ohms/vertical div.)

Fig.1 reveals the sealed enclosure to be tuned to 80Hz or so, while nearfield measurements indicated the crossover between the front drive-unit and the two downward-facing woofers to lie at 250Hz. As can be seen from fig.2, the bass is quite underdamped, with a significant rise in output apparent between 100Hz and 200Hz. But above that range, the Elan is surprisingly flat on-axis, at least through the mid-treble frequencies. A suckout appears an octave above the presence region, with a return then to the reference level between 9kHz and 17kHz, followed by a steep ultrasonic rolloff. It is quite possible that this lack of midtreble energy correlates with the laidback tonal balance I noted in my auditioning.

Fig.2 Evett & Shaw Elan, anechoic response on-axis at 50", averaged across 30 degrees horizontal window and corrected for microphone response, with the complex sum of the nearfield woofer and midrange responses plotted below 400Hz.

As can be seen from the speaker's vertical dispersion plot (fig.3), the front drive-unit's output off-axis falls off quite rapidly above 8kHz, once the listener moves above or below the central axis. This can also be seen in the plot of horizontal dispersion (fig.4), while a similar graph showing the actual measured responses—rather than the differences between those responses and the axial reference (fig.5)—reveals that the top-octave output is very beamy.

Fig.3 Evett & Shaw Elan, vertical response family at 50", from back to front: differences in response 45 degrees–5 degrees above axis, reference response, differences in response 5 degrees–45 degrees below axis.

Fig.4 Evett & Shaw Elan, lateral response family at 50", normalized to response on tweeter axis, from back to front: differences in response 90 degrees–5 degrees off-axis, reference response, differences in response 5 degrees–90 degrees off-axis.

Fig.5 Evett & Shaw Elan, lateral response family at 50", from back to front: response 90 degrees–5 degrees off-axis, axial response, response 5 degrees–90 degrees off-axis.

As a result, the speaker's free-field in-room response (fig.6) rolls off quite steadily above 2kHz. This is very definitely a speaker that needs to be listened to on-axis in the nearfield. Note also in fig.6 that, without the boundary reinforcement to be expected from a desk under the speaker or a wall behind it, the Elan's low frequencies roll off below the exaggerated 125–160Hz region.

Fig.6 Evett & Shaw Elan, spatially averaged, 1/3-octave, free-field response in JA's listening room.

In the time domain, the Elan's impulse response (not shown) has a coherent shape (as you might expect from a single drive-unit covering the entire range above 250Hz), if overlaid with some high-frequency ringing. The step response (fig.7) is also nicely time-coherent, with a good triangle shape from the frontal driver, followed by the lazier, rather underdamped output from the twin woofers. The speaker's cumulative spectral-decay plot (fig.8) is very clean, which correlates with its perceived lack of high-frequency grain.—John Atkinson

Fig.7 Evett & Shaw Elan, on-axis step response at 50" (5ms time window, 30kHz bandwidth).

Fig.8 Evett & Shaw Elan, cumulative spectral-decay plot at 50" (0.15ms risetime).

Evett & Shaw
3565 South West Temple No.14
Salt Lake City, UT 84115
(801) 293-8286